MDF Extension

What is MDF Extension?

File extensions are very important parts of the computer world because it makes clear that what kind of data is present in the file. MDF extension that concerns with master database is the primary data file of SQL Server which includes all the records, information and metadata of a SQL Server such as logon accounts, linked servers, endpoints and system configuration setting. Therefore, you cannot start the SQL Server without master database if it becomes corrupt or inaccessible.

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Restrictions and Recommendations of Master Database

There are the some operations that cannot be performed on the Master Database.

  • Adding files or file groups.
  • Changing collation. The default collation is the server collation.
  • Changing the database owner. master is owned by dbo.
  • Creating a full-text catalog or full-text index.
  • Creating triggers on system tables in the database.
  • Dropping the database.
  • Dropping the guest user from the database.
  • Enabling change data capture.
  • Participating in database mirroring.
  • Removing the primary filegroup, primary data file, or log file.
  • Renaming the database or primary filegroup.
  • Setting the database to OFFLINE.
  • Setting the database or primary filegroup to READ_ONLY.

You need to consider some points before going to work with the Master Database

  • Always have a current backup of the master database available.
  • Do not create user objects in master. Otherwise, master must be backed up more frequently.
  • Do not set the TRUSTWORTHY option to ON for the master database.
  • Back up the master database as soon as possible after the following operations:
  • Creating, modifying, or dropping any database
  • Changing server or database configuration values
  • Modifying or adding logon accounts

Are you unable to access/open Master.MDF files on Windows?

When Windows gives you error messages like:

  • “Cannot Open MDF File”
  • "Server can't find the requested database table"
  • "The process could not execute 'sp_replcmds' on server"
  • "The file *.mdf is missing and needs to restore"

If you are getting these error messages then your registry may be damaged or you need to identify a program which interrupts you to open Master.MDF database file. For this kind of problem, we recommended you to try SQL Recovery tool that can quickly sort out the problems related to Master.MDF files.

How to Restore/Rebuild the Master Database in SQL Server 2000, 2005 and 2008?

Get SysTools SQL Recovery tool which is one of the best solutions that easily rebuild master database of SQL Server and quickly restore master database in SQL Server. Using SQL Recovery tool you can successfully regain deleted items like: tables, triggers, view, user defined data types, rules and definitions, indexes & constraints etc. SQL Recovery tool supports all master database files created by SQL Server 2000, 2005 and 2008.

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